Linus:
One thing that I have to say about kdramas is that they tend to have too many episodes and fluff in the season, though. It seems that there is a pre-set number of episodes that tend to run in 16 or 20 segments. To stretch them to the predestined number of episodes, they often put a bunch of really corny plot devices. Also, some shows maybe would benefit from having 2 shorter seasons.
Other than that, I totally agree that having an American show that spans god-knows-how-many seasons tends to ruin them. I like having only 1 season and knowing that it will end after that.
The writing is pretty flimsy overall in Korean dramas.
I'm watching That Man Oh Soo as an example and there's so much pointless time-wasting. They have a supernatural element but it's completely neglected in favor of angst and other stuff... like they really could have and should have fleshed out the supernatural element a lot more. The show is halfway to its end and I still don't really understand why there is any supernatural element at all in this show. I suspect we'll see its desperate appearance to force something on the two leads at the last minute but that feels like a cheap gimmick.
American network TV is pretty awful because a show can get renewed constantly and you see the writers run out of material.
But there is a lot of good stuff on smaller premium networks like HBO or FX or Starz. Netflix, Amazon and other streaming sites seem to let their writers and directors stick to a certain number of seasons without pushing too hard for more.